1. Field of the Invention
The invention relates generally to image sensors, methods for fabrication thereof and design structures for fabrication thereof. More particularly, the invention relates to image sensors with enhanced light capture.
2. Description of the Related Art
Solid state image sensors are popular optoelectronic components that find use in various imaging technology applications. Particularly common are solid state image sensors that are used as active light capture and imaging elements within digital cameras.
Solid state image sensors may be fabricated using any of several semiconductor technologies for the active light capture and imaging elements. Charge coupled devices are known as more traditional solid state image sensor light capture and imaging elements. Complementary metal oxide semiconductor (CMOS) devices provide yet another semiconductor based active light capture and imaging element for use within a solid state image sensor. Solid state image sensors predicated upon CMOS semiconductor devices are generally more desirable insofar as such CMOS based solid state image sensors typically consume less power in comparison with other types of solid state image sensors.
While solid state image sensors in general, and CMOS image sensors more particularly, are desirable within the optoelectronic component fabrication art, solid state image sensors in general; and CMOS image sensors more particularly, are not entirely without problems. In particular, light capture efficiency and light conversion efficiency are often relevant parameters that may be difficult to optimize within solid state image sensors. To that end, solid state image sensor designs that include superior light capture efficiency and/or superior light conversion efficiency are desirable.
Various solid state image sensor structures and designs, and methods for fabrication thereof, are known in the optoelectronic art.
For example, Pi et al., in U.S. Pub. No. 2002/0020846, teaches a backside illuminated photodiode array that may be used within the context of a solid state image sensor. The backside illuminated photodiode array may be coupled with a scintillation material to provide a scintillation based backside illuminated photodiode array.
In addition, Rhodes, in U.S. Pat. No. 6,465,786, teaches a deep infrared photodiode that may be used within a CMOS image sensor. The deep infrared photodiode includes an infrared absorptive silicide layer, as well as an optional reflective layer.
Finally, Mouli, in U.S. Pat. No. 7,279,764, teaches a CMOS image sensor that includes a silicon based resonant cavity. The silicon based resonant cavity provides an increased light absorption for the CMOS image sensor at long wavelengths.
Solid state image sensors, including in particular CMOS image sensors, are likely to be of continued interest and continued importance as solid state image sensor technology advances. Thus, desirable are solid state image sensors, and methods for fabrication thereof, that provide for accurate and efficient light capture and light conversion.